Study On The Preparation Of Magnetic Composite TiO₂Hollow Microspheres And Application For The Drug Delivery

In recent years, with the development of medical technology, drug controlledrelease preparations have gradually become the emphasis in parmaceutics research,the key of which is the choice of the drug carrier. Inorganic hollow materials haveunique structure and properties, such as large specific surface area, low surfaceenergy, strong permeability and easy modification. Their internal cavity can load alot of drugs, and the porous shell can be used as the channel of drug release,therefore, they are considered to have the most potencial in the field of drugdelivery system.Magnetic nanomaterials have shown great application prospect in magneticresonance imaging, targeted drugs, magnetic targeted hypertherm and many otherbiomedical field, because of their superparamagnetic and high saturationmagnetization. If combining the hollow materials and the magnetic materials,making it have a large specific surface area and superparamagnetic, then thepreparation of drug carrier which both have the slow release performance andtargeted transport function will be possible, and it will also have importantsignificance in the treatment of cancer and other disease.In this paper, we firstly prepare the TiO2hollow microspheres byhydrothermal alkaline etching method with SiO2as a template, and systematiclyinvestgate the coating procedure of SiO2@TiO2core-shell microsphere, as well asthe hydrothermal process. The results show that, SiO2@TiO2core-shellmicrosphere have a uniform particle size and better monodispersity when adding0.15g SiO2,0.3mL NH3·H2O,1.0mL TBOT and reactin for24h, the TiO2shellthickness is about15nm; Using NaOH and NH3·H2O as a etchant, the TiO2hollowmicrospheres have a larger specific surface area when the pH is12and9,respectively, which is121m2/g and133m2/g. Taking IBU an the model drug,investgating the drug controlled release property of the two TiO2hollowmicrospheres with the largest specific surface area, the results show that, t he drugloading capacity of the two hollow microsphere is93.0mg/g and131.9mg/g, andrelease approximately80%and100%within24h, respectively, comparing with therelease curve of pure IBU, show a sustained release property to IBU.Then we prepared Fe3O4@SiO2core-shell microspheres with300nm Fe3O4asa templat, and investgate the influence of TEOS addition to the core-shell structure,the results show that Fe3O4@SiO2core-shell microspheres have bettermonodispersity when adding0.15mL TEOS. Then prepared Fe3O4@SiO2@TiO2multi-layer core-shell microsphere using the optimal conditions obtained in thelast chapter, and finally remove the SiO2layer under the condition of NaOH(pH=12), NH3·H2O(pH=9) respectively, to obtain the two magneticcomposite TiO2hollow microspheres, and study their drug release properties. Theresults show that Fe3O4is translated into γ-Fe2O3through a hydrothermal process,but still has superparamagnetic and large saturation magnetization. The specificsurface area of the two magnetic composite TiO2hollow microspheres is61m2/g,the drug loading capacity is33.1mg/g and92.7mg/g, the release efficienty within24h is70%and100%, compared with the release curve of pure IBU, showing asustained release property to IBU. The prepared magnetic composite TiO2hollowmicrospheres involving the sustained release property as well as thesuperparamagnetism, so they will have important significance in the field ofbiomedicine such as targeted therapy.